1. Technical Field
The present disclosure relates generally to an imaging system and, particularly, to an imaging system having both an extended depth of focus (EDoF) mode and an autofocus (AF) mode.
2. Description of Related Art
In optics, particularly as it relates to photography and film, the depth of field (DoF) is a region of a scene that appears acceptably sharpness in the image. Although a lens can precisely focus at only one distance, the decrease in sharpness is gradual on each side of the focused distance. Within the DoF, the unsharpness is imperceptible under normal viewing conditions. The DoF is determined by the camera-to-subject distance, the lens focal length, the lens f-number (the ratio of lens focal length to aperture diameter), and the format size or circle of confusion criterion.
An Autofocus (AF) imaging system focuses automatically and mechanically. Adjustment of the optical system has to be constantly performed when focusing on subjects at various distances, and considerable energy is thereby consumed.
An extended depth of focus (EDoF) imaging system includes a program for extending DoF. The EDoF imaging system processes image importations in a digital image process to give a resulting image with increased sharpness. When focus is set to a hyperfocal distance, the DoF extends from half the hyperfocal distance to infinity, and such a DoF is the largest possible. However, acquiring sufficient depth of field for the EDoF imaging system is particularly challenging within a small camera-to-subject distance, and the resulting image of neighboring subjects may be blurred.
Such EDoF imaging systems do not cooperate with the AF imaging system. Therefore, it is desirable to provide an imaging system which can overcome the described limitations.